Deck 9: Advanced Array Concepts

Question 1

When working with two-dimensional arrays, the length field holds the number of rows in an array and each row has a length field that holds the number of columns in the row.

Answer 1

True

Question 2

With a two-dimensional array, the ____ field holds the number of rows in the array.

A) size
B) capacity
C) row
D) length

Answer 2

D

Question 3

When using the Arrays.binarySearch() method, it is not necessary for the list to be in order because the binarySearch() method will sort the items when called.

Answer 3

False

Question 4

In a(n) ____, you repeatedly compare pairs of items, swapping them if they are out of order, eventually creating a sorted list.

A) range match
B) bubble sort
C) enhanced for loop
D) float sort

Question 5

The bubble sort is the fastest and most efficient sorting technique.

Question 6

Swapping two values can be accomplished with two statements.

Question 7

____ is the process of arranging a series of objects in some logical order.

A) Passing
B) Organizing
C) Sorting
D) Sending

Question 8

The Arrays class ____ method puts a particular value in each element of the array.

A) binarySearch
B) fill
C) equals
D) search

Question 9

When using an insertion sort, each list element is examined one at a time and moved down if the tested element should be inserted before them.

Question 10

How would you create an array named someNumbers that holds three rows and four columns?

A) int[][] someNumbers = new int[4][3];
B) int[][] someNumbers = new int[3][4];
C) int[] someNumbers = new int[3][4];
D) double[][] someNumbers = new int[3][4];

Question 11

Which Java statement creates a jagged array with six rows?

A) double [][] sales = new double[6][4]
B) double [][] sales = new double[4][6]
C) double [][] sales = new double[6][]
D) double [][] sales = new double[][6]

Question 12

When you pass a two-dimensional array to a method, you pass the array name just as you do with a one-dimensional array.

Question 13

You can think of the single dimension of a single dimensional array as the height of the array.

Question 14

The Arrays class ____ methods are a new feature in Java 8 that makes sorting more efficient when thousands or millions of objects need to be sorted.

A) compare
B) equals
C) parallelSort
D) fill

Question 15

When mathematicians use a two-dimensional array, they often call it a ____.

A) grid
B) net
C) matrix
D) mesh

Question 16

If you do not provide values for the elements in a two-dimensional numeric array, the values default to null .

Question 17

An array that you can picture as a column of values, and whose elements you can access using one subscript, is a ____ array.

A) single-dimensional
B) two-dimensional
C) parallel
D) column

Question 18

To declare a two-dimensional array in Java, you type two sets of ____ after the array type.

A) { }
B) [ ]
C) ( )
D) < >

Question 19

The simplest possible sort involves two values that are out of order.

Question 20

Since the ArrayList class is part of the java.util package, you can use the java.util.*; import statement to access it.

Question 21

int[][] myVals = {{2, 4, 6},                   {1, 8, 9},
                  {1, 3, 5, 7}};
Using the above array, what is the value of myVals[1].length ?

A) 1
B) 7
C) 3
D) 6

Question 22

The ArrayList class ____ method returns the current ArrayList size.

A) size
B) capacity
C) length
D) rows

Question 23

The ArrayList class ____ method removes an item from an ArrayList at a specified location.

A) delete
B) get
C) erase
D) remove

Question 24

The ArrayList class ____ method retrieves an item from a specified location in an ArrayList .

A) extract
B) get
C) peek
D) retrieve

Question 25

int[][] myVals = {{2, 4, 6, 8},                   {20, 40, 60, 80} };
Using the above two-dimensional array, what is the value of myVals[1][2] ?

A) 4
B) 60
C) 6
D) 40

Question 26

When you place objects in order beginning with the object that has the lowest value, you are sorting in ____ order.

A) ascending
B) reverse
C) descending
D) lowest

Question 27

Regarding enumerations, the ____ method returns the name of the calling constant object.

A) toString
B) constName
C) ordinal
D) nameOf

Question 28

int[][] myVals = {{2, 4, 6},                   {1, 3, 5, 7}};
Using the above array, what is the value of myVals.length ?

A) 1
B) 2
C) 4
D) 5

Question 29

A method that receives a two-dimensional array uses two ____ pairs following the data type in the parameter list of the method header.

A) curly brace
B) parenthesis
C) bracket
D) dot

Question 30

You can add an item at any point in a(n) ____ container and the array size expands automatically to accommodate the new item.

A) ArrayList
B) Array
C) ResizableArray
D) array

Question 31

In Java, you create an enumerated data type in a statement that uses the keyword ____.

A) new
B) sequence
C) collection
D) enum

Question 32

Regarding enumerations, the ____ method returns an integer that represents the constant's position in the list of constants; as with arrays, the first position is 0.

A) valueAt
B) positionOf
C) ordinal
D) indexOf

Question 33

When you place objects in order beginning with the object that has the highest value, you are sorting in ____ order.

A) ascending
B) reverse
C) descending
D) lowest

Question 34

Which of the following describes a data type for which only appropriate behaviors are allowed?

A) value-neutral
B) type-safe
C) static
D) data-cast

Question 35

The  Arrays  class ____ method assigns the specified value to each element of the specified array.

A) assign()
B) init()
C) sort()
D) fill()

Question 36

Programmers often refer to a ____ search as a "divide and conquer" procedure.

A) bubble
B) binary
C) division
D) split

Question 37

An ArrayList 's ____ is the number of items it can hold without having to increase its size.

A) length
B) buffer
C) capacity
D) size

Question 38

The  Arrays  class ____ method sorts the specified array into ascending order.

A) assign()
B) init()
C) sort()
D) fill()

Question 39

The negative integer returned by the binarySearch() method when the value is not found is the negative equivalent of the array ____.

A) type
B) scope
C) size
D) length

Question 40

double[][] empSales = new double[5][]; The above statement declares a(n) ____ array.

A) insertion
B) sort
C) jagged
D) boolean

Question 50

How can you sort arrays of objects?

Question 51

Write the code for bubble sorting a someNums array of integers.

Question 55

How can you pass a two-dimensional array to a method? Provide some examples.

Question 56

What is sorting and how are objects organized as a result of being sorted?

Question 58

Describe how to visualize the following array. How would you identify the location of the 99 that is stored in the array?
int[][] someNumbers = {{8, 9, 10, 11},
{1, 3, 12, 15},
{5, 9, 44, 99} };

Question 61

What import statements must be used before you can use an ArrayList class?

Question 62

public class EnumExample
{
    enum Day {SUNDAY, MONDAY, TUESDAY, WEDNESDAY,
              THURSDAY, FRIDAY, SATURDAY };
​
    Day day;
​
    public EnumExample(Day day)
    {
        this.day = day;
    }
​
    public void giveFeedback()
    {
        switch (day)
        {
            case MONDAY:
                System.out.println("Mondays are bad.");
                break;
​
            case FRIDAY:
                System.out.println("Fridays are better.");
                break;
​
            case SATURDAY: case SUNDAY:
                System.out.println("Weekends are best.");
                break;
​
            default:
                System.out.println("Midweek days are so-so.");
                break;
        }
     }
​
    public static void main(String[] args)
    {
        EnumExample firstDay = new EnumExample(Day.MONDAY);
        firstDay.giveFeedback();
        EnumExample thirdDay = new EnumExample(Day.WEDNESDAY);
        thirdDay.giveFeedback();
        EnumExample fifthDay = new EnumExample(Day.FRIDAY);
        fifthDay.giveFeedback();
        EnumExample sixthDay = new EnumExample(Day.SATURDAY);
        sixthDay.giveFeedback();
        EnumExample seventhDay = new EnumExample(Day.SUNDAY);
        seventhDay.giveFeedback();
    }
}
Using the above enumeration and code, what will be the output when the program is executed?

Question 63

What are some of the advantages of creating an enumeration type?

Question 64

Using the ArrayList add() method, write the statement to insert "July" in the first position of the months ArrayList . Describe what would happen if the position number is invalid for the ArrayList .

Question 65

Write the statement to declare an ArrayList named myVals with a capacity of 15 items. Explain the importance of capacity when working with an ArrayList .

Question 66

int[][] studentScores = {{70, 82, 90, 68},
{95, 75, 67, 89},
{98, 79, 57, 81}};
Using the above two-dimensional array, what is the value of studentScores[0][0] ? What is the value of studentScores[2][3] ? What is the value of studentScores[1][2] ? Describe how arrays reference values with subscripts.

Question 67

import javax.swing.*;
class FindPoints
{
   public static void main(String[] args)
   {
      int[][] points =
     {{10, 20, 30},
      {20, 40, 60},
      {40, 60, 80}};
      String prompt;
      int class;
      int level;
      prompt = JOptionPane.showInputDialog(null, "Class: ");
      class = Integer.parseInt(prompt);
      prompt = JOptionPane.showInputDialog(null, "Level: ");
      level = Integer.parseInt(prompt);
      JOption.showMessageDialog(null, "Your points: " + ---complete code here-----);
   }
}
The above code depicts a two-dimensional array named points that refers to a Class and Level to determine a point value. Complete the JOption command so that the code will determine a point value based on the points array.

Question 68

​import javax.swing.*;
class FindPoints
{
   public static void main(String[] args)
   {
      int[][] points =
     {{10, 20, 30},
      {20, 40, 60},
      {40, 60, 80}};
      String prompt;
      int class;
      int level;
      prompt = JOptionPane.showInputDialog(null, "Class: ");
      class = Integer.parseInt(prompt);
      prompt = JOptionPane.showInputDialog(null, "Level: ");
      level = Integer.parseInt(prompt);
​
      JOption.showMessageDialog(null, "Your points: " + points[class][level]);
   }
}
The above code depicts a two-dimensional array named points that refers to a Class and Level to determine a point value. If a user inputs a Class of 1 and a Level of 2, what point value will be displayed when the program executes? Explain how you arrived at your answer.

Question 69

import java.util.*;
public class myArray
{
    public static void main(String[] args)
    {
      int myVals = new int[4];
      -----Code here-----
      display("My values are: ", myVals);
    }
    public static void display(String message, int array[])
    {
       int arraySize = array.length;
       System.out.print(message);
       for(int x = 0; x < arraySize; ++x)
          System.out.print(array[x] + " ");
    }
}
Using the above code, complete the indicated section with a fill method() to fill each array element with a value of 2. What will be displayed after the display() method is executed?

Question 70

How can you use the length field with a two-dimensional array? Show an example two-dimensional array declaration and provide the length values for the example array.

Question 71

int[][] myVals = {{10, 15, 20, 25},
                  {30, 35, 40, 45, 50, 55, 60},
                  {65, 70, 75, 80, 85, 90}};
Using the above array, what is the value of myVals.length ? What is the value of myVals[1].length ? What is the value of myVals[2].length ? Explain how you determined these values.

Question 72

What are some of the advantages of the ArrayList class over the Arrays class?

Question 73

Declare an ArrayList that declares a list of strings with a capacity of 20.

Question 74

int[][] myVals = new int[3][]
myVals[0] = new int[3];
myVals[1] = new int[10];
myVals[2] = new int[5];
The above code depicts a jagged array. What does this mean? Describe the rows and columns that make up this array.

Question 75

What is the advantage of declaring an ArrayList with a specified type?

Question 76

import java.util.*;
public class sortArray
{
     public static void main(String[] args)
    {
       double[] lengths = {120.0, 0.5, 0.0, 999.0, 77.3};
       Arrays.sort(lengths);
         System.out.println(Arrays.toString(lengths));
    }
}
Using the above code, what will be the output of the println statement when the code is executed?

Question 77

import java.util.*;
import javax.swing.*;
public class binary_search
{
    public static void main(String[] args)
   {
           int myNums[]={2, 44, 5, 66, 78, 90, 23, 66};
           int point, find = 78;
           point = Arrays.binarySearch(myNums, find);
           System.out.println("Element found at index " + point);
  
    }
}
Using the above code, what output will be displayed when the program is executed? Describe how the binarySearch() method functions.

Question 78

Write the statement that assigns the integer value 20 to the first column of the first row of an array named myVals .

Question 79

Write the statement to declare a three-by-four array of integers with the elements initialized to zero. Name the array myArray .

Question 80

enum Color {RED, GREEN, BLUE}
public class EnumOrdinal
{
    public static void main(String[] args)
   {
     ---Code here---
     ---Code here---
     ---Code here---
    }
}
The above code demonstrates the use of the enum ordinal() method to get the ordinal value of an enum constant. Fill in the indicated lines with println() statements that will get the ordinal of the enumeration constant. Describe the output that will display when the code is executed.